export default class SocketService {
    // 单例
    static instance = null
    static get Instance() {
        if (!this.instance) {
            this.instance = new SocketService()
        }
        return this.instance
    }
    //和服务端连接的socket对象
    ws = null

    // 存储回调函数
    callBackMapping = {}

    //标识是否连接成功
    connected = false
    //记录重发（send）连接的重试次数
    sendRetryCount = 0
    //记录服务器连接失败（onclose）重新连接的次数
    connectRetryCount = 0

    //定义服务器的连接方法
    connect() {
        //连接服务器
        if (!window.WebSocket) {
            return console.log('您的浏览器不支持webSocket')
        }
        this.ws = new WebSocket('ws://localhost:9998')

        //连接服务端成功事件
        this.ws.onopen = ()=>{
            console.log('连接服务端成功了')
            this.connected = true
            //重置重新连接的次数
            this.connectRetryCount = 0
        }
        //连接服务端失败事件
        this.ws.onclose = ()=>{
            console.log('连接服务端失败了')
            this.connected = false
            this.connectRetryCount++
            setTimeout(()=>{
                this.connect()
            },this.connectRetryCount * 500)
        }
        //接收服务端发送过来的数据
        this.ws.onmessage = msg=>{
            console.log('接收到服务端发送过来的数据')
            // console.log(msg.data)
            const recvData = JSON.parse(msg.data)
            const socketType = recvData.socketType
            //判断回调函数是否存在
            if(this.callBackMapping[socketType]){
                const action = recvData.action
                if(action === 'getData'){
                    const realData = JSON.parse(recvData.data)
                    this.callBackMapping[socketType].call(this,realData)
                }else if(action === 'fullScreen'){
                    this.callBackMapping[socketType].call(this,recvData)
                }else if(action === 'themeChange'){
                    this.callBackMapping[socketType].call(this,recvData)
                }
            }
        }
    }
    //回调函数的注册
    registerCallBack(socketType,callBack){
        this.callBackMapping[socketType] = callBack
    }
    //取消某个回调函数
    unRegisterCallBack(socketType){
        this.callBackMapping[socketType] = null
    }
    //定义发送数据的方法
    send(data){
        //判断有没有连接成功
        if(this.connected){
            this.sendRetryCount = 0
            this.ws.send(JSON.stringify(data))
        }else{
            this.sendRetryCount++
            setTimeout(()=>{
                this.send(data)
            },this.sendRetryCount * 500)
        }
    }
}